Postharvest physiology
Sepideh Shirani Rad; Mohammad Sayyari; Mohammad Ali Zolfigol
Abstract
Introduction
Horticultural waste is one of the top challenges these days. As the population increases, food loss and waste, which has a serious impact on the environment and human health. Horticultural waste is rich in nutrients, polysaccharides and antimicrobial compounds that can be used in the ...
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Introduction
Horticultural waste is one of the top challenges these days. As the population increases, food loss and waste, which has a serious impact on the environment and human health. Horticultural waste is rich in nutrients, polysaccharides and antimicrobial compounds that can be used in the production of edible coatings. Edible coatings protect fruit from nutrient and mineral loss and extend shelf life. Strawberry fruit is one of the commercial horticultural crops because it contains important and diverse sources of natural antioxidants, flavonoids, phenolic acids and minerals. However, the fruit is highly perishable due to its high respiratory rate and metabolic activity, soft texture and lack of protective skin, which can lead to moisture loss, mechanical damage and fungal damage during harvesting, handling and packing. It is estimated that approximately 30% of strawberry fruit is wasted during the post-harvest stage before reaching the consumer. Therefore, reducing the destruction rate of its quantitative and qualitative properties is considered one of the most important challenges. Plant Extract Edible Coating (PEEC) is an environmentally friendly edible coating. Like other edible coatings, PEEC is a thin layer of material applied to the surface of a product. Pomegranate peel extract has biological activities such as antibacterial, antiviral, antioxidant, anti-inflammatory, and antifungal. This extract was used alone or in combination with other post-harvest treatments to preserve product quality. Tomatoes contain secondary metabolites called steroidal glycoalkaloids. These compounds primarily act as crop protection agents against insects, bacteria, parasites, viruses and fungi. This study evaluated the efficacy of pomegranate peel extract and tomato seedlings in maintaining strawberry fruit quality during cold storage and reducing post-harvest waste.
Materials and Methods
Healthy fruits with uniform size, shape, and color were carefully selected from strawberries harvested from an orchard in Kamyaran, Kurdistan. We conducted a study to investigate the effects of coating these strawberries with pomegranate peel extract (1%) and tomato seedling extract (1%) on their physiological and qualitative responses. The fruits were coated with the respective plant extracts and subsequently stored at 4 ± 1°C and 90–95% relative humidity for a duration of 15 days. Strawberry quality was analyzed on the first day of storage and on days 5, 10 and 15. Various qualitative factors such as weight loss, firmness pH, total soluble solids content, titratable acidity, total phenolic content, total anthocyanin content, total antioxidant activity, total flavonoid content, ascorbic acid, color and decay severity were evaluated. Statistical analysis of the data was performed using SAS (version 9.4) and mean comparisons were performed using the Duncan multiple range test.
Results and Discussion
The study on the property retention and long-term cold storage time of pomegranate peel and tomato seedling extracts coating showed that a concentration of 1% of the extracts used have a significant effect on strawberry fruit quality and phytochemical parameters. It was shown to have a significant impact on strawberry fruit quality and phytochemical parameters, improving compared to the control treatment during cultivation. Weight loss increased with all treatments during storage. After 5 days of storage, no differences between treatments were discernible, but at the end of storage all treatments showed a clear decrease in fruit weight. Pomegranate peel and tomato seedling extracts reduced weight loss by 12% and 15%, respectively, while the control significantly reduced weight loss by 26%. Despite the decrease in fruit tissue firmness during storage, the firmness of the plant extract-coated fruit was maintained and significantly different from the control. PH remained at low levels for all treatments compared to controls. The total acid and total soluble solids content of the fruit are affected by the treatments considered, the storage, and the combination of times and treatments. The total content of phenolic compounds reached 223 mg gallic acid and 236 mg gallic acid per 100 g fresh weight on the 10th and 15th storage days after treatment with pomegranate peel extract. For tomato seedling extract, this corresponds to 207 mg and 182 mg gallic acid per 100 g fresh weight. The total anthocyanin content in all fruits decreases with increasing storage time, but this trend increases after 10 days when tomato seedlings are treated. In all fruits, various treatments increase anthocyanin levels throughout the storage time. ANOVA of antioxidant activity showed no significant effects on treatment-independent and chronotherapy-interaction effects, while the time-independent effect showed a significant effect at 5%. The greatest antioxidant activity is associated with pomegranate peel extract. The frequency of this feature in treatment decreased with increasing storage time. During the treatment period, there was a progressive increase in antioxidant activity from the 10th to the 15th day, demonstrating a significant difference compared to the beginning of the treatment. Average comparison results revealed a slight but significant difference in the treatments concerning flavonoid content. Analysis of variance and comparison of mean results indicated a significant difference in ascorbic acid content during storage among the different treatments. Color indices remained consistent across all treatments. The 15-day shelf life of strawberries was assessed, and the treatments employed effectively reduced decay rates during storage. Upon analysis, it was determined that the 1% concentration of pomegranate peel extract exhibited the highest efficacy in suppressing the severity of spoilage.
Conclusion
Residues from various agricultural sectors have a variety of uses, including their properties as preservatives that extend the shelf life of perishable fruits and enhance the nutritional value of fruits and vegetables. Replacing plant extracts with synthetic compounds can play an important role in preserving the characteristics and quality of strawberry fruits during storage. Based on the results of this study, an edible coating containing plant extracts from pomegranate peel and tomato seedling as natural preservatives was used to extend the shelf life and enhance the nutritional quality of strawberry fruits during cold storage. Finally, using natural compounds such as plant extracts from agricultural waste is a safe and healthy way to manage and preserve the properties of post-harvest agricultural products.
Fardin Ghanbari; Mohammad Sayyari
Abstract
Introduction: Due to its low level of calorie and being as an excellent source of C and A vitamins as well as containing lycopene as a powerful antioxidant, Tomato (solanum lycopersicum, 2n=2 x=24), is extensively consumed in the world. According to the statistics presented in 2013, following China, ...
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Introduction: Due to its low level of calorie and being as an excellent source of C and A vitamins as well as containing lycopene as a powerful antioxidant, Tomato (solanum lycopersicum, 2n=2 x=24), is extensively consumed in the world. According to the statistics presented in 2013, following China, United States, Turkey and Egypt, Iran ranked sixth in tomato production (6174182 kg per year) world tomato production. Similar to other tropical crops, tomato is sensitive to chilling stress. The chilling stress is considered as one of the environmental factors influencing growth and development of many plants including tomato. Applying different environmental conditions and cultivation techniques within transplant production can mitigate the chilling stress of seedlings. The seedling hardening is one of the simple technique being employed to physiological characters of plant, so as to induce subsequent stress resistance. This phenomenon is so-called cross tolerance and it means that exposing plants to stressful conditions can induce plant tolerance to upcoming stresses. Therefore, the objective of our study was to investigate the effect of drought hardening and chilling stress on tomato plant growth and productivity in field condition.
Materials and Methods: This experiment was conducted in greenhouse and research laboratories of agricultural college of Bu Ali Sina University. First of all, the seeds of tomato cv. C.H Falat, were sown in pots filled with perlite and vermiculite (ratio 2:1) and then maintained under natural light and at 25±2°C / 18±2°C (day/night). At four-leaf full development stage, seedlings were subjected to seven-day drought stress simulated with polyethylene glycol 6000 (PEG) at three levels: control (0% PEG), moderate drought stress (10 % PEG equaling to 0.18 Mpa osmotic potential) and severe drought stress (20% PEG equaling to 0.57 Mpa osmotic potential). After employing different levels of drought stress and consequently placing them in recovery for 48 h, they were exposed to chilling stress and non-chilling stress condition. For imposing chilling stress, the seedlings were transferred into growth chamber under 3°C for 6 days and 6 h per day. After receiving chilling stress treatments, the produced seedlings, were planted in the field.
Results and Discussion: In the present study, drought pretreatment reduced the effects of cold stress on fruit yield and quality. Results revealed that, the growth and yield of tomato plants were significantly increased by drought stress pretreatment in field condition. Herein, Seedlings without receiving drought pretreatment slowly grew and gained lower yield than those receiving drought. Some traits such as higher fruit size and shelf life and low number of decayed end blossom fruits were gained by drought application. The highest growth and yield rates were obtained through 10% PEG. These results indicate that drought stress at seedling stage increases the yield of tomato without harmful effects on fruit quality. The results showed that in 0% PEG treatment (control), chilling stress increased the number of days for flowering and fruiting, which indicates the growth retardation in this plant under cold stress condition. Drought pre-treatment using PEG increased the thickness of the pericarp and its post-harvest life, which may indicate the maintenance of the effects of initial stress in all stages of vegetative and reproductive growth. It has been reported that cold stress directly affects the growth potential of plants that interfere with the proper production of plants by disrupting metabolic reactions and indirectly by preventing the absorption of water by plants and oxidative stress (Hussain et al., 2018). In the present study, pre-treatment of drought reduced the destructive effects of chilling stress on fruit size. These results show that pre-treatment of drought (especially 10% PEG) had a significant effect on increasing fruit size and preventing its fruit yield reduction due to cold treatment. Similarly, Paradosi et al. (1987) reported that water stress in tomato plants increased its tolerance to cold and maintained the growth of tomato plants and its yield in cold greenhouse conditions. So far, there have been no reports of interactions between environmental stresses on fruit size, but the effects of drought stress on tomato fruit have been studied.
Conclusion: In general, the results of this experiment showed that the effects of drought pre-treatment on seedling remain in the next stages of tomato growth and can have beneficial effects on growth and yield of tomato in field conditions.
Mohammad Sayyari; Reza Gharibi
Abstract
Introduction: Strawberry (fragaria×ananassa Duch.) fruit characterized by short storage life, often estimated last less than one week even under optimum conditions at 8°C. The loss of fruit quality is often caused by gray mold (Botrytis cinerea) that is the most frequent reported postharvest disease ...
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Introduction: Strawberry (fragaria×ananassa Duch.) fruit characterized by short storage life, often estimated last less than one week even under optimum conditions at 8°C. The loss of fruit quality is often caused by gray mold (Botrytis cinerea) that is the most frequent reported postharvest disease in strawberry during storage (6). In recent years, considerable attention has given to elimination of synthetic chemical and fungicides application and development of various alternative strategies for controlling fruit and vegetables diseases (2). One strategy is replacement of natural products with plant origin such as essential oil and methyl salicylate (MeSA). Essential oils are volatile, natural and complex compounds characterized by a strong odor formed by aromatic plants in form of secondary metabolites. In nature, essential similar oils that extract from lavender (Lavandula angustifolia) play an important role in protection of the plants against pathogen incidence that can be replaced by synthetic fungicides (1, 4 and 14). MeSA is also a volatile natural compound synthesized from salicylic acid which has an important role in the plant defense-mechanism, as well as plant growth and development (5, 19 and 20). Therefore, the main objective of this research was to study the effects of MeSA and lavender essential oil (LEO) on decay control caused by Botrytis cinerea as well as post-harvest quality indices of strawberry fruits during cold storage.
Material and Methods: First, antifungal activity was studied by using a contact assay (in vitro), which produces hyphal growth inhibition. Briefly, potato dextrose agar (PDA) plates were prepared using 8 cm diameter glass petri dishes and inhibitory percentage was determined. For in-vivo assessment of LEO and MeSA effects on Botrytis-caused fungal disease control, the experiment was conducted as factorial in completely randomized design (CRD) with 3 replicates. The treatments were 3 concentration of LEO including 0, 500 and 1000 µl L-1 and 3 level of MeSA including 0, 0.1 and 0.2 mM. After treatment, the fruits were inoculated by Botrytis suspension and transferred to storage and quality parameters were evaluated after 7, 14 and 21 days. At each sampling time, disease incidence, weight loss, titratable acidity, pH, soluble solids content, vitamin C and antioxidant activity were measured.
Results and Discussion: The results showed that both LEO and MeSA treatments had significant effects on inhibition of mycelium growth within in-vitro condition (p < 0.05). Inhibition rate of mycelium growth significantly improved by LEO and MeSA concentration increase of, (Table 1). At in-vivo assessment, diseases incidence of treated fruits with 500 µl L-1 LEO and 0.1 mM MeSA were 32% and 64% lower than untreated fruits, respectively (Fig. 1 and 2). During storage period, the percentage of infected fruits increased. In addition, LEO and MeSA treatments affected quality parameters of strawberry fruits including titratable acidity, soluble solids content, vitamin C and antioxidant activity. Treated fruits had a high content of soluble solids, vitamin C and antioxidant activity in comparison to untreated fruits (Table 3 and 4). Probably ascorbic acid decreased through fungal infection duo to cell wall break down during storage. Any factors such as essential oil and salicylate that inhibit fungal growth can help preserving vitamin C in stored products. High level of vitamin C and antioxidant activity was observed in treated fruits with 0.1 mM MeSA and 500 µl L-1 LEO. In controlling weight loss of fruits, 0.2 mM of MeSA and 500 µl L-1 of LEO had significant effects, although MeSA was more effective than LEO treatments, possibly due to elimination of respiration rates and fungi infection (Table 4). Therefore, LEO and MeSA with fungicide effects could be replaced with synthetic fungicides in controlling fungal diseases of strawberry and maintain fruits quality during storage.
Conclusion: In conclusion, our results showed that LEO and MeSA treatments could be safe and used to prevent infection of strawberry during storage, although LEO was more effective than MeSA treatments. Concentration of 500 μl L-1 of LEO and 0.1 mM MeSA could control fungal infection of fruits during storage. Also, LEO and MeSA treatments can extend shelf life for over the minimum period required to transit strawberries to foreign markets and without affecting quality, adversely. However, future studies are necessary to fully understand the mechanisms by which LEO and MeSA treatments may act as a fungicide and increase their postharvest life.
Zahra Khazaei; Mohammad Sayyary; Mehdi Seydi
Abstract
Drought, withnegative impacts on plant growth and development, isa major abiotic stress. In order to decreasing drought stress injuries and recognizing red peppers tolerance physiology against drought stress in greenhouse conditions, an experiment with three levels of drought stress (irrigation at 100, ...
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Drought, withnegative impacts on plant growth and development, isa major abiotic stress. In order to decreasing drought stress injuries and recognizing red peppers tolerance physiology against drought stress in greenhouse conditions, an experiment with three levels of drought stress (irrigation at 100, 60 and 30% of field capacity) and four concentrations of 5-aminolevolinic acid ((ALA; 0, 0.25, 0.5, and 1 mM)with four replications in an experimental was 3×4 factorial experiments in a randomized completely design was conducted in greenhouse of Agricultural Faculty of Ilam University. In the end of experiments, parameters such as ascorbate peroxidase activity, total antioxidant activity, malondialdehyde content, ascorbic acid, relative water content, plant height and number of lateral buds was evaluated. The results showed that with increasing drought stress severity the growth parameters decreased significantly but ascorbate peroxidase activities, total antioxidant capacity, malondialdehyde and ascorbic acid content increased. Foliar application of AHA reduced malondialdehyde content and improved other evaluated traits. ALA protected cell membranes by reducing malondialdehyde content and lipid peroxidation. In addition, ALA with increasing ascorbate peroxidase activity, total antioxidant capacity and ascorbic acid contents in plants improved physiological traits and drought stress resistance.
